Helms made his WWF debut on the July 5, 2001 episode of SmackDown!, using the name "Hollywood" Gregory Helms. He was part of the Invasion storyline as a member of The Alliance losing his Cruiserweight Championship in a one-on-one match to another Alliance member, Billy Kidman.
Helms began wrestling as "The Hurricane" on August 27, and also began wearing a superhero costume. That night, he won the European Championship from Matt Hardy with help from Ivory, but lost it to Bradshaw on October 22, 2001. In September 2001, Helms formed a tag team with Lance Storm who was now managed by Ivory and Helms later picked up a sidekick, in Molly Holly who began to call herself "Mighty Molly", and the two came to the arena in a custom "Hurri-Cycle" (with Molly in the sidecar). The team of Helms and Storm began feuds with teams like The Hardy Boyz and Big Show and Spike Dudley. Helms and Storm got a shot at the WWE Tag Team Championship against The Hardy Boyz at No Mercy 2001 in a losing effort.
During 2002, The Hurricane won the WWE Hardcore Championship at WrestleMania X8, but Molly betrayed him, hitting him in the back of the head with a frying pan, and defeating him for the championship. Helms was later drafted to the SmackDown! brand following the brand extension, and he won the Cruiserweight Championship from Tajiri and Billy Kidman in a triple threat match. He lost it to Jamie Noble at King of the Ring. Later in 2002, he was traded to Raw, won the World Tag Team Titles with Kane, and held them for around a month in an alliance known as Hurri-Kane.
In 2003, Hurricane feuded with The Rock. In backstage segments, The Rock referred to The Hurricane as "The Hamburglar". The feud culminated in a match on Raw, in which The Rock dominated. Hurricane, however, was able to roll up The Rock from behind after The Rock was distracted by Stone Cold Steve Austin's appearance on the ramp.
In late 2003, Hurricane "discovered" Rosey's potential as a superhero and christened him "Rosey, the Super Hero in Training". On May 1, at Backlash, Rosey and The Hurricane defeated La Résistance in the finals of a Tag Team Turmoil match to win the World Tag Team Championship. Not long after winning the championship, Stacy Keibler joined Rosey and The Hurricane as their sidekick, "Super Stacy". In August 2005, Rosey and The Hurricane lost Keibler as their sidekick when she and Christy Hemme were traded to the SmackDown! brand. On September 5, 2005 Hurricane and Rosey were defeated by Lance Cade and Trevor Murdoch during Cade and Murdoch's debut match on Raw. As a result, Cade and Murdoch earned a title match at the Unforgiven pay-per-view. During the title match, Murdoch delivered an elevated DDT on The Hurricane to the outside. The DDT caused Hurricane to suffer a storyline "stinger" and allowed Cade and Murdoch to beat the injured Hurricane later in the match to win the World Tag Team Titles.
At the 2006 Royal Rumble, he participated in an Open Invitational match for the Cruiserweight Championship and won, even though he was a Raw superstar and the championship was defended solely on SmackDown!. As a result, he returned to the SmackDown! brand in February 2006 to start a feud with Nunzio, Kid Kash and the other cruiserweights. During this time, Helms defeated Nunzio in a one-on-one match. The next week, he was supposed to defend against Kid Kash, but Kash was away on a family emergency, so Scotty 2 Hotty took his place. Helms defeated him and declared that he was better than all the other cruiserweights. As a result, all the cruiserweights at the show invaded the ring and attacked Helms. It was later announced by SmackDown! General Manager Theodore Long that at the No Way Out pay-per-view event, Helms would face all the cruiserweights in a match for the title. Helms was able to retain the championship. Later, Long mandated that Helms had to defend his title against a cruiserweight each week on SmackDown! to prove that he truly was better than all the cruiserweights. Helm's first defense under this new rule was against Psicosis of The Mexicools; Helms retained by cheating.
In early March 2006, Helms suffered a broken nose. After complaining to Long about having to wrestle on the March 10 episode of SmackDown!, Long told Helms that he did not have to defend his title, but put Helms in a champion versus champion match against the United States Champion, Chris Benoit. During the match, Helms attempted to leave, but was blocked by other cruiserweights who threw Helms back into the ring, resulting in Helms losing the match. Helms underwent successful surgery on his nose and was expected to miss five to six weeks. During this time SmackDown! announcers stated that Helms had a no-compete clause in his contract allowing him to waive the thirty-day title defense rule due to any injury. Helms returned to the ring on the April 28 episode of SmackDown!, teaming with MNM to face Super Crazy, London and Kendrick in a six-man tag team match. Helms continued to defend his belt during pay-per-views, but he made more regular appearances on SmackDown!'s sister show, Velocity.
Helms continued defending his title against other cruiserweights, while on occasion facing off against SmackDown!'s other title holders in champion versus champion matches. Helms faced World Heavyweight Champion Rey Mysterio on June 16 and United States Champion Bobby Lashley on July 7 but lost both matches. Eventually, Helms became the longest cruiserweight champion in WWE history, as well as the longest reigning champion of any kind in SmackDown! history. For much of late 2006, he feuded with Matt Hardy, with whom Helms exchanged several victories in matches on SmackDown!. In Helms' hometown of Raleigh, North Carolina, at the 2006 No Mercy pay-per-view, Hardy beat Helms. The two rivals also joined opposing teams at Survivor Series, where Helms was in Team Rated-RKO, and Hardy was a member of Team DX; Team Rated-RKO lost the match.
Helms went on to feud with Jimmy Wang Yang over the Cruiserweight Title, after a tag team match in which Matt Hardy and Yang defeated Helms and Sylvan. The feud ended after Helms defeated him to retain the title at Armageddon in December 2006.
In 2007, Helms once again feuded with the entire Cruiserweight division on SmackDown!. During this feud, Helms' reign as Cruiserweight Champion came to an end at No Way Out, when he was unable to win a Cruiserweight open invitational, which saw Chavo Guerrero win the championship. Shortly after losing the championship, Helms formed a tag team with Guerrero, but they didn't win any matches as a team.
On May 18, 2007, WWE reported that Helms had broken two vertebrae in his neck, one of which was pressing on his spinal cord. He underwent surgery with Dr. Lloyd Youngblood to repair them approximately a week later. Following the surgery, Helms was announced to be out for a year due to his neck injury.
Helms returned on the September 19, 2008, episode of SmackDown in a non-wrestling role. Throughout the show, he appeared in short video promos, called "Hurrapops", referring to himself as "Hurricane Helms", a modified version of his old ring name "The Hurricane", and mocked heel superstars including Shelton Benjamin and Curt Hawkins and Zack Ryder. In the following weeks, he mocked several other superstars in the "Hurrapops", ending each promo with the phrase, "I'm just sayin'!" On the November 28 episode of SmackDown, a "Hurrapop" appeared in which Helms announced that he would make his return to the ring on the next episode of SmackDown. On the December 5 episode of SmackDown, Helms defeated Montel Vontavious Porter in his ring return. Helms was quickly scripted into a feud with the United States Champion Shelton Benjamin, defeating him in two non-title matches on SmackDown, although he failed to win a championship match on December 26.
On the January 16th 2009 episode of SmackDown, during a Cutting Edge segment, he appeared alongside R-Truth, Matt Hardy, and Jimmy Wang Yang as they were escorting Jeff Hardy out of the ring for medical care after a pyro accident occurred.
On April 15, 2009, Helms was drafted to the ECW brand as part of the 2009 Supplemental Draft. Helms made his ECW debut as a backstage interviewer on April 28, 2009, reverting to his Gregory Helms ring name, interviewing Evan Bourne. He started a storyline where, while he was interviewing someone, a scripted accident would occur, leading to Helms leaving the interview seconds before the person in distress was saved by The Hurricane. On the August 11, 2009 episode of ECW, Helms was attacked by Paul Burchill after Helms denied being The Hurricane. The Hurricane later attacked Burchill in the ring dressed in his Hurricane attire, to save Yoshi Tatsu. The next week on ECW, he made his in-ring debut for the brand as The Hurricane, and defeated Burchill. He continued to feud with Burchill, who attempted to expose The Hurricane's true identity, until the November 17 episode of ECW when The Hurricane defeated Burchill in a mask versus career match.
On February 26, 2010, Helms was released from his WWE contract.